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9. Filtering a queryset by checking if a field attribute is {{{None}}} is equivalent to testing if the corresponding database column is {{{NULL}}}. So {{{qs.filter(foo=None)}}} is now identical to {{{qs.filter(foo__isnull=True)}}}.

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10. An {{{update()}}} method has been added to querysets to allow multiple objects to have an attribute updated in a single SQL query.

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11. `Q` classes now fully support `&`, `|` and `~` to combine them in pairs as conjunctions or disjunctions or to negate the sense of a filter, respectively (`&` and `|` were previously supported, but returned a different type of class). Thus the `QAnd`, `QOr` and `QNot` classes are no longer required and have been deprecated. Using them raises a warning (although they still work as before).